Electric-arc lamp.



No. 638,703. Patented Dec. I2, |899. W. J. COCHRAN.

ELECTRIC ARC LAMP.

(Application led Jan. 23, 1899.)

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NITED STATES PATENT OFFICE.

'WALTER J. COCHRAN, OF LE ROY, NEV YORK, ASSIGNOR, BY DIRECT AND MESNEASSIGNMENTS, TO DAVID J. BISSELL, OF SAME PLACE.

ELECTRIC-ARC LAM P.

srncrrrenrrolv forming part of Laers Patent No. 638,703, dated December12, 1899'.

Application filed January 23, 1899. Serial No. 703,191. (No model.)

Be it known that I, VALTER J. COCHRAN, a citizen of the United States,residing in the village of Le Roy, county of Genesee, and State of NewYork, have invented a new and useful Electric-Arc Lamp, which may beused with any kind of current, of which the following is aspecification.

My invention relates to improvements in electricearc lamps, and moreparticularly to improvements in an arc-lamp designed to prevent thecasting of a shadow.

The objects of my invention are to provide for such a lamp means of asimple and effective construction to automatically produce and maintainan arc of the desired length and in the desired position with the leastpossible friction of the operating parts, with the use of a small numberof parts to be controlled by the current and by the employment of acurrent of less strength than is usually necessary for a lamp of thischaracter, to provide for maintaining the arc at all times in a fixedposition when the lamp is burning, to make a lamp compact in all itsparts, and to secure a greater convenience in the operation of cleaningand trimming.

In the accompanying drawings, Figure l is a vertical section, partly inelevation, of a lamp with my improvements attached thereto; Fig. 2, arear view in elevation of part of lamp, showing coil-s upportingbrackets; Fig. 3, a detail top plan of one of the clutches; Fig. 4, adetail plan of cover-plate, and Fig. 5 a section of one of armssupporting the cover on line o: a: of Fig. 4.

My invention is herein illustrated and described as applied to andadapted for use with an alternating inclosed arc-lamp.

Referring to the drawings, a is the handle of the lamp, by means ofwhich it is supported. The handle is swiveled at its lower ends tostud-bolts l), which pass through a plate c and are rounded at their lower ends to receive nuts d. Rubber washers e are clamped between ashoulder of the bolt and the plate and between the nut cl and the plate,respectively, by metal washers f, and the handle thus effectivelyinsulated from the plate and its connected parts.

Secured to or preferably integral with the plate c are the radial arms gg and t 7L, adaptied to support the cover t'. Arms g are provided attheir outer ends with spring-catches consisting of stiff outwardly-bentvertical springs j, each having a tooth or ledge 7a, on which a flangeor bead of the cover at the upper end thereof is adapted to besupported. lVhen the parts are in position, the ledge 7s engages withthe llange 19 on the cover. On 6o the ends of arms 7L and under sidethereof are cut-away portions Z, which lit over the rixn ofthe cover andby their shoulders hold the same steady. The covert' isV made of lead,

so as to deaden the vibrations thereof, and thus prevent the vibrationof the lamp itself. Integral with the plate c are the lugs m at frontand rear of the lamp having arms n. Between the rear arm andcorresponding standard o of a bracket p is clamped by screw 7oconnections the iron core q of a choke-coil r. The core is also screwedto the arm of the front lug. The core is a horseshoe-core and isseparated at the point of support between the bracket and the rearplate-lug. The bracket p is provided with legs s, to which is secured bycountersunkscrews a circular plate or disk t, made of porcelain orothersuitable insulating material. Formed on the bracket are the splitsleevese,havingclamping-screws, 8o by which the screws are clamped toand support the metal tubes tu, which are insulated from said sleeves bymica or other suitable insulating material. The tubes ru extend fromunder the plates c and their lower ends converge. These tubes areadapted to contain the carbons and their holders. The carbonsxare placedin the tubes and are adapted to be fed down therein by gravity. Over theupper end of cach carbon is fitted a metal 9o slotted sleeve y, betweenwhich and a metal plug e', driven in the sleeve, are clampedspring-brushes l, which are bent or curved near their upper ends, andthereby make clectrical contact with the tubes. The tubes cX- tend onlyashort distance below the bracket p, and from the tubes the carbonsextend to and through the plate t, converging a short distance below theplate and forming the are. The carbons may converge at any suitable rooangle, that shown in the drawings being about sixty-'live degrees.

The under surface of plate t is made concave at the center in order toform a reflecting-surface 2 for the arc, the plate being made of orfaced with suitable material for this purpose. The concavity 2 forms acorresponding convexity in the upper surface of the plate.

A small glass globe 3, hinged to the bottom of plate t and provided witha headed screw to fasten it to the plate, is adapted to inclose the arc.A larger hinged globe l, provided with aspring-catch and secured to theplate, incloses the smaller globe. In practice the inner globe may bedispensed with, as it will be found that the outer globe can make thearc-space suiiiciently air-tight.

Mounted on bracket p is a workin g magnet 5. Vithin the magnet is asliding armature or core G. A pistou-rod 7 is secured to said armatureand at its upper end is provided with a piston-head S, adapted to workin a dash-pot 9. The dash-pot is pivoted to a small yoke 10, which inturn .is pivoted by right-angle arms to another yoke 11, that is rivetedor screwed to the plate c. To the lower end of the piston-rod is secureda horizon tal arm 12, ol fiber or other suitable insulating material,and to each end of this arm is pivoted a link 13. The lower end of eachlink is pivotally connected to the jaw 14E, embracing the carbon, andthis jaw is also pivoted to a jaw 15, said jaws together forming aclutch adapted to engage the carbon. When the clutches are at rest andthe carbon-points down together and out of operation, the jaws 14 willrest evenly on the ledge 1G of the conveX portion of the plate t.

The circuit is made through binding-post 17, working magnet 5, throughone of the Wirings of choke-coil 7', then through the carbons and tubesto binding-post 18.

The connection is made to any one of the several coils of the choke-coilin accordance with the pressure required to accord with the voltage ofthe current in producing an arc of the desired length.

The operation of the invention is as follows: The carbons and otherparts of the lamp are shown in working position. The clutches beingdrawn up by the armature, the inner jaws of clutches will engage andsupport the carbons. The normal length of the arc is determined by thestrength of the current and the strength of the current is determined bythe resistance of the choke-coil. The relative location of the workingmagnet, armature, and clutches is such that when the current is ofnormal strength the carbons will be held in the proper position tomaintain'the normal length of the arc. When the ends of the carbons inburning are consumed and separated, the resistance of the lengthened arcwill break or diminish the current, lessening the attraction between theworking magnet and the armature and causing the latter, with the arm 12,to descend and the clutches to strike the plate t, whereupon the grip ofthe inner jaws 14E of the clutches upon the carbons will be relaxed andthe carbons will feed down and approach each other. Instantly the fullstrength of the current will be established and the armature will beattracted upwardly to its normal position, picking up the carbons bymeans of the pivoted clutches, and thus striking the proper arc. Thepiston attached to the armature and moving in the dash-pot 8 will checkthe movement of the armature and prevent itfrom being retracted too farby the renewed attraction of the magnet. It will be seen that thepick-up device set forth will lift the carbons in the direction of theiraxes. This mode of separating the carbons to strike the arc will affordthe least possible resistance to the working of the current. Since theclutches are attached directly to the carbons, which, together with thearmature, slide freely in their bearings, there will be very littleweight an d practically no friction to oppose the movement of the adjusted parts, and hence but a slight current is required for suchmovement. The action of the clutches is almost instantaneous, and allsputtering is thus obviated.

When the lamp is not in use and the circuit not made, the ends of thecarbons will rest against each other, and the jaws 11i of the clutcheswill rest on the ledge 1G.

The ashes from the carbons will fall into the globe 3 and can be readilyremoved therefrom when the globe is unhooked. The burned carbons can bereadily removed and replaced by new ones, no set-screws or clamps beingrequired for their support and adjustment, the slotted holder g/ havingthe action of a spring-holder for centering the carbon and electricallyconnecting carbon and tube.

The insulating carbon-guiding plate tenables the insulation usuallyemployed between the parts in electrical circuit and thesupporting-frame to be dispensed with, while the construction andlocation of the plate enable the reflecting-surface to be readily formedthereon.

By making the cover of lead the vibrations of the cover and lamp areneutralized.

rlhe cover may be easily removed from the spring-catches and may besupported when removed by chains or other suitable means.

It is obvious that numerous changes in the details of construction maybe made without departing from the principle of my invention.

lVhat I claim is* 1. In an arc-lamp, diagonally-converging tubes likedto the frame of the lamp, gravityfed carbons sliding in said tubes, incombination with an arc-maintaining and pick-up device comprising anarmature, pivoted clutches directly engaging said carbons, and grippingthe carbons on the attracted movement of the armature, andlaterally-yielding connections between said armature and clutches,whereby the carbons are picked up in the direction of their axes and atthe same time separated, substantially as described.

IOO

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2. In an arc-lamp, diagonally-converging carbons, a magnet and armatureor core sliding in said magnet, and limited in its attracted movementsolely by the resistance of the arc and strength of the current, incombination with pick-up clutches, said clutches provided with means togrip and lift said carbons, and laterally-yielding connections betweensaid armature and clutches, whereby the carbons Will be lifted in thedirections of their axes and at the same time separated, substantiallyas described.

3. In an arc-lamp, diagonally-converging carbons, fixed holding-tubesfor said carbons, a pair ot' pivotally-connected jaws embracing each ofsaid carbons, a link pivoted to one of said jaws of each pair, a bar towhich the opposite ends of said links are pivoted in combination withelectrical means forautomatically controlling the opening and closing otsaid jaws, and means With which said jaws are adapted to contact torelax the same, substantially as described.

4. In an arcelamp, in combination with gravity-fed diagonally-convergingcarbons, Xed holding-tubes for said carbons, a verticallymoving armatureand means to attract the same, a piston attached to said armature, adash-pot in which said piston moves, clutches consisting of pivotedjaws, means to pivotally connect said arma-ture and a jaw of eachclutch, said clutches adapted to grip the carbons for holding them inarcing position and to. release them. to permit their feed, said carbonsadjustable in the directions ot' their axes and means to govern therelease of the clutches, substantially as described.

5. The combination With the converging carbons of a clutching deviceconsisting of a top cross-bar, between the carbons and above theconvergence of the same, a link hung to each end of said bar, annnerclutch-jaw pivoted to each of said links, an outer clutchjaw pivotedto the inner one, said inner and outer jaws embracing a carbon, anarmature to which said top cross-bar is secured, said inner janT adaptedto grip the carbon in the upward movement of the bar, substantially asdescribed.

l/VALTER J. COCHRAN.

Witnesses:

FRANK W. RUBY, FREDK. G. AircnrsoN.

